Insert Link Button Grayed Out: Not Working in Visual Editor

Hello all,

I’m having an issue with the visual editor. When I want to add a link, I highlight the text, then go to click the insert/edit link button in the visual editor. But, it is grayed out, and I am unable to add or edit links. I am able to add a link in the text view, but I would love to be able to continue adding links in the visual editor.

I am running WordPress 4.1 using the Graphene Theme. All plugins and themes are up to date. I have tried all the following, clearing the browser cache after each attempt:

• Deactivated all plugins in the WordPress dashboard.
• Deactivated all plugins by renaming the folder through FTP.
• Switched to the default Twenty Fifteen theme.
• Replaced the wp-content/admin/includes folder from a fresh download of WordPress.
• Replaced the wp-content/includes folder from a fresh download of WordPress.

Nothing made a difference – the link button still doesn’t work. The weird thing is that I’m running two other sites with almost identical plugins and themes, and they aren’t having this issue. There have a been a few issues with this site recently- I’m thinking something got broken in the meantime.

Do you have any insight or ideas? While it’s a problem I can work around, I’d rather not – and I’d rather have it fixed.

Thanks!